There is a minus sign in the call:

agg^.attach(@graph_buffer.data, IMAGE_WIDTH, IMAGE_HEIGHT, -(IMAGE_WIDTH * RGB_WIDTH))

Removing it will flip the Y axis.

With regard to color, there may be two options:

1) the ideal way would be to specify the rgb order of a pixel format in the Agg_2D constructor. The m_pixFormat has a m_order field with the type order_type defined in agg_color.pas; have not figured it yet

2) knowing the R and B channels are swapped, you can do all your drawing with colors there R and B are switched.


Stefan


On 06/13/2017 12:42 PM, James Richters wrote:
I've just realized that the red and blue channels are reversed.  The sample
program aggpas_ptcgraph_output.pas has the star filled in with a red fade
and a blue series of random lines while the original test.png file had a
blue fade in the star with red random lines.   Also, the image is flipped on
the Y axis compared to the original example. The small green square is in
the upper left corner of test.png, but it is in the lower left corner of
aggpas_ptcgraph_output.pas

I've been able to duplicate the results of test.png by shifting the left 5
bits 11 positions to the right and the right 5 bits 11 positions to the left
and flipping the Y axis,  but I can only do that with putpixel and a nested
loop, which is quite a bit slower than putimage.

Any ideas how I can build the data correctly so putimage will work?

James

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